A heater, which is used to increase external temperature, has used various methods and has been used as various usages.
In particular, among heaters installed in a vehicle engine compartment, a heater serving to perform heating is configured to heat an interior of a vehicle by allowing a heat exchange medium used for lowering a temperature of an engine to circulate a heater core to heat external air.
However, among engines, a diesel engine has a high heat exchange rate, and thus requires a longer time to heat a heat exchange medium which cools an engine at the time of an initial starting of a vehicle, as compared with a gasoline engine.
Therefore, in case of a vehicle in which a diesel engine is mounted, the heating of the heat exchange medium is delayed after the initial starting during the winter season and thus an initial indoor heating performance may be degraded.
To solve the above-mentioned problem, an air heating heater for a vehicle, using a method of directly heating air ventilated to an interior of a vehicle using various devices has been proposed.
In this case, the air heating heater may more increase the heating performance by directly heating air, but occupies a space corresponding to a size of the heater under the situation in which it is difficult to secure a sufficient space in the engine compartment due to the tendency of miniaturization and high efficiency which may be a cause hindering the miniaturization.
In particular, a cartridge heater using a nichrome wire may not easily control temperature, when air is not ventilated to the heater, may overheat, have an insulating problem due to a high voltage, and have a risk of fire.
Further, an air conditioning device for a vehicle using a positive temperature coefficient (PTC) heater has been proposed in Japanese Patent Laid-Open Publication No. 2009-255739. Meanwhile, a PTC heater according to the related art is illustrated in FIG. 1.
In FIG. 1, an air flow direction is represented by an arrow and the PTC heater illustrated in FIG. 1 is configured to include a heat source unit 11 including a PTC element, a heat radiating unit 12 which effectively discharges heat by contacting the heat source unit 11, and a housing 20 which protects a terminal unit, the heat source unit 11, and the heat radiating unit 12 by enclosing them.
The PTC heater according to the related art may be different in terms of some of the detailed components, but as the heat source unit is formed in parallel with the air flow direction, the forming area of the heat source unit directly affects the heat radiating performance, such that there is a limitation of reducing a thickness (in the air flow direction) of the PTC heater.
In particular, in the PTC heater, since the electrical problem may occur when the heat radiating conditions are poor, the heat radiating unit including heat radiating fins is required. As a result, the manufacturing and assembling process of the heat radiating unit may be cumbersome and when the heat radiation is not effectively performed, the durability of the PTC heater may be generally degraded.
FIG. 2 illustrates an example of an air conditioning device for a vehicle using the PTC heater.
An air conditioning device 60 for a vehicle illustrated in FIG. 2 is configured to include a floor vent 31 of which the opening/closing degree is controlled by each door 31d, 32d, and 33d, an air conditioning case 30 in which a defrost vent 32 and a face vent 33 are formed, an evaporator 41 which is mounted in the air conditioning case 30 to cool air, a heater core 42 in which high-temperature cooling water flows to heat air, a PTC heater 43 mounted at a back side of the heater core 42 in the air flow direction, and a temperature door 50 which controls an opening/closing degree of a cooling air passage and a warming air passage.
In this case, the PTC heater is disposed to be spaced apart from the heater core by a predetermined distance and occupies a space in the air conditioning case as much, which may lead to degradation in spatial efficiency.
Further, since the PTC heater is mainly disposed at a central region of the heater core in a height direction to prevent a pressure of air from dropping, save costs, and the like, air passing through upper and lower regions in which the PTC heater is not disposed moves in the state in which air is not appropriately heated, thereby causing the degradation in heating performance.
A flow of air moving in which the air is not appropriately heated is represented by a dotted line arrow.
Therefore, a demand for development of a heater which can be directly heat exchanged with air, increase the heat exchange performance to more improve the heating performance, be miniaturized, be easily controlled, and prevent the problems caused by overheating to more improve safety has increased.